Comment by ventana

I actually started re-reading Crime and Punishment right after writing my previous comment, because I barely remember anything after many years. These are the second and the third paragraphs, and reading this text now, in my forties, I perfectly understand everything that's written, and the emotions the protagonist feels, because I know by my very own experience what it is to pay rent, to be in debt, and to have no money. But as a teenager? No freaking idea.

  He had successfully avoided meeting his landlady on the staircase.
  His garret was under the roof of a high, five-storied house and
  was more like a cupboard than a room. The landlady who provided
  him with garret, dinners, and attendance, lived on the floor below,
  and every time he went out he was obliged to pass her kitchen,
  the door of which invariably stood open. And each time he passed,
  the young man had a sick, frightened feeling, which made him scowl
  and feel ashamed. He was hopelessly in debt to his landlady, and
  was afraid of meeting her.
  
  This was not because he was cowardly and abject, quite the contrary;
  but for some time past he had been in an overstrained irritable
  condition, verging on hypochondria. He had become so completely
  absorbed in himself, and isolated from his fellows that he dreaded
  meeting, not only his landlady, but anyone at all. He was crushed
  by poverty, but the anxieties of his position had of late ceased
  to weigh upon him. He had given up attending to matters of practical
  importance; he had lost all desire to do so. Nothing that any landlady
  could do had a real terror for him. But to be stopped on the stairs,
  to be forced to listen to her trivial, irrelevant gossip, to pestering
  demands for payment, threats and complaints, and to rack his brains
  for excuses, to prevaricate, to lie—no, rather than that, he would
  creep down the stairs like a cat and slip out unseen.

But as for the chemistry, biology, math, or anything else, I don't see any reason why a teenager won't be able to understand that.